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Showing results for: [ Zhang, Songbo ]
We have re-processed all the observations in the Parkes pulsar data archive obtained during the first four years of the Parkes multibeam receiver and have discovered two new fast radio bursts (FRBs) a... morend five single pulse candidates (SPCs) from unknown sources, but with Galactic dispersion measures. These signals were only detected in a single beam of the receiver suggesting that they are unlikely to be terrestrial. There are no known pulsars in the pointing direction of the five SPCs and therefore are likely giant pulses from currently unknown pulsars. Using the Ultra Wideband Low (UWL) receiver we have opportunity to detect repeating signals from the two FRBs and to confirm the five SPCs. Our previous observations have obtained new detections for one of these targets and therefore confirming that source. Therefore we propose for more observation in an attempt to confirm the remainder and to study the newly discovered source.less
Australia Telescope National Facility - P1040 - Follow-up observations of transient events detected in the Parkes data archive - Published 27 Jan 2021
Intermittent pulsars are a major topic of current pulsar research as they provide a direct link between studies of pulsar emission and irregularities in the rotation of the pulsars. The new Ultra-Wide... more-Low(UWL) receiver provides unprecedented frequency coverage and will allow us to study the emission properties of the intermittent pulsars in great detail. We request observations with the UWL receiver to intermittent pulsars. These are pulsars whose emission switches on and off at long intervals from days to years. We will determine the distribution and frequency dependence of the time scales, look for weak or bursty emission in the off states and determine the bandwidth of the on/off emission process, the spectral characteristics of the emission, the evolution of pulse energy distribution over wide-band and search for possible link between long- and short-term emission variability. These observations will provide insights into how these pulsars emit and how that emission is changing in time and as a function of frequency.less
Australia Telescope National Facility - P1071 - Study of intermittent pulsars with UWL - Published 26 Jan 2021
Australia Telescope National Facility - P1071 - Study of intermittent pulsars with UWL - Published 25 Jan 2021
The Parkes Pulsar Timing Array (PPTA) project has three primary goals: (a) detection of gravitational waves from astronomical sources, (b) establishment of a pulsar timescale, and (c) improvement of o... moreur understanding of Solar-system dynamics. The PPTA is the oldest of three international pulsar timing groups. We have the smallest telescope and the smallest group, but the best measurements and the best results. Our bound on the strength of the incoherent gravitational wave background is the only bound which significantly constrains theoretical models. We have maintained our leading position because: we have the southern sky; we have a small but well-focussed group; we have the best-calibrated receivers; and we have been able to observe with an almost regular cadence of 15 to 20 days over a wide bandwidth. With this proposal we aim to maintain our pre-eminent position in the field. Unlike most observing proposals, this is a continuing proposal for which the observations will continue to improve bounds on ultra-low-frequency gravitational waves until they are finally detected. Continued Parkes observations will remain valuable at least until the first stage of the SKA is able to improve on our sensitivity and observing cadence. Even after the gravitational wave background is detected we will want to continue observations in support of the nascent field of gravitational wave astronomy!less
Australia Telescope National Facility - P456 - A millisecond pulsar timing array - Published 24 Jan 2021
Australia Telescope National Facility - P456 - A millisecond pulsar timing array - Published 19 Jan 2021
Australia Telescope National Facility - P456 - A millisecond pulsar timing array - Published 12 Jan 2021
Australia Telescope National Facility - P456 - A millisecond pulsar timing array - Published 05 Jan 2021
Fast Radio Bursts (FRBs) have extremely high brightness temperature, owing to their short-duration and prominent flux from the distant universe. The studies on emission mechanism of FRBs have met bott... moreleneck for a long time unless a complete spectrum is measured. We propose to observe a new repeating FRB source, FRB 180301, using the Parkes ultra-wide-bandwidth receiver (UWL). This source was initially found by Parkes multibeam receivers and confirmed repetition by the FAST telescope. The source is still active until Jun 2020 from FAST follow-ups. It’s an ideal opportunity to capture comprehensive spectral information using the Parkes UWL. We demonstrate that the beam coverage is feasible and 30-hr observations are required for at least one detection.less
Australia Telescope National Facility - P1061 - Observing the repeating FRB 180301 with the Parkes UWL - Published 03 Jan 2021
Australia Telescope National Facility - P456 - A millisecond pulsar timing array - Published 03 Jan 2021
Australia Telescope National Facility - P1061 - Observing the repeating FRB 180301 with the Parkes UWL - Published 02 Jan 2021
Australia Telescope National Facility - P1061 - Observing the repeating FRB 180301 with the Parkes UWL - Published 01 Jan 2021
Australia Telescope National Facility - P1061 - Observing the repeating FRB 180301 with the Parkes UWL - Published 30 Dec 2020
Australia Telescope National Facility - P1061 - Observing the repeating FRB 180301 with the Parkes UWL - Published 27 Dec 2020
Australia Telescope National Facility - P1061 - Observing the repeating FRB 180301 with the Parkes UWL - Published 25 Dec 2020
Australia Telescope National Facility - P456 - A millisecond pulsar timing array - Published 23 Dec 2020
In this proposal we request observations from the Parkes radio telescope to research bright periodic non-drift amplitude modulation pulsars. In these pulsar, the central and trailing components of the... more pulse profiles switch between a strong mode and a weak mode periodically. We plan to use the new Parkes Ultra-Wideband-Low receiver that will provide us with information at widely separated frequency bands. The mode switch pattern in a wide frequency range will be obtained and can confirm whether this effect is dependent on observation frequency. We will also obtain the polarisation profiles of the two states over wide-band. The observations will be used to investigate whether this phenomenon is associated with the presence of a core component in the pulse profile. Finally, we will compare them with periodical nulling pulsars and try to find some possible connection between them.less
Australia Telescope National Facility - P1057 - A study of unusual periodic fluctuations in radio pulsars - Published 23 Dec 2020
We propose to monitor the potential repeating FRBs in the Southern Sky with luminosity di- chotomy criterion. With a success of luminosity-guided detection of a repeating source by FAST, we can contin... moreue to search for more repeaters hidden in current FRB sample according to luminosity dichotomy. Specifically, we select FRB 171020 and FRB 180923 as the targets of proposed obser- vations, which are located in the repeater population in the luminosity function. We demonstrate that the observing with 20 hours for each source is optimistic using Parkes ultra-wide-bandwidth receiver (UWL), if there are repeaters among them.less
Australia Telescope National Facility - P1062 - Monitoring the repeating FRB candidates in the Southern Sky - Published 22 Dec 2020
We propose observations with the ultra-wide-bandwidth, low frequency receiver (UWL) installed at the Parkes telescope to carry out single pulse study of millisecond pulsars. We have selected two of th... moree brightest pulsars that are regularly observed by the Parkes Pulsar Timing Array. Our observations will enable statistical properties study of single pulses with ultra-wide-bandwidth, measuring jitter noise level of the linear and circular polarization states as well as in the total intensity signal, measuring jitter bandwidth and how jitter noise decorrelates with frequency. The UWL receiver, with its much wider bandwidth, will provide unique opportunity for study of jitter noise evolution with frequency.less
Australia Telescope National Facility - P1043 - Single pulse study of millisecond pulsars using the Parkes wideband receiver - Published 21 Dec 2020
We have re-processed all the observations in the Parkes pulsar data archive obtained during the first four years of the Parkes multibeam receiver and have discovered two new FRBs and five single pulse... more candidates (SPCs) from unknown sources, but with Galactic dispersion measures. These signals were only detected in a single beam of the receiver suggesting that they are unlikely to be terrestrial. There are no known pulsars in the pointing direction of the five SPCs and therefore are likely giant pulses from currently unknown pulsars. Using the Ultra Wideband Low (UWL) receiver we have opportunity to detect repeating signals from the two FRBs and to confirm the five SPCs. As all these signals were detected in the 20 cm band, the UWL provides the opportunity to observe stronger emission in other observing bands.less
Australia Telescope National Facility - P1040 - Follow-up observations of transient events detected in the Parkes data archive - Published 20 Dec 2020
Australia Telescope National Facility - P456 - A millisecond pulsar timing array - Published 19 Dec 2020
The Parkes Ultra-wide-bandwidth receiver enables, for the first time with the Parkes telescope, a commensal high time and high frequency resolution survey. We will observe Baade's window in which we ... moreare guaranteed detections of pulsars and spectral lines. Our science drivers are diverse and range from understanding scattering, to detecting new pulsars, to searching for galaxies in the zone of avoidance, probing the globular cluster at the centre of the window and studying OH circumstellar masers and CO-dark molecular gas. The observing strategy and processing software developed for this survey will be applicable to all future Parkes surveys with the wide-band receiver or cyrogenically-cooled phased array feed.less
Australia Telescope National Facility - P1067 - A wide-band survey of Baade's Window in the time and frequency domains - Published 16 Dec 2020
Australia Telescope National Facility - P1067 - A wide-band survey of Baade's Window in the time and frequency domains - Published 15 Dec 2020
